Durability of responses in patients with metastatic renal cell carcinoma treated with high-dose interleukin-2 (HD IL-2).

Abstract

511 Background: HD IL-2 is FDA approved for advanced renal cell carcinoma (mRCC), however, the data supporting its use is 23 years old. In 2011, a HD IL-2 patient database was established called PROCLAIMSM, and comprises the largest active prospective collection of data from mRCC and metastatic melanoma (MM) patients receiving HD IL-2 treatment and provides longitudinal real-time insights into the clinical impact of sequencing drug treatments. These data report on the outcomes and interactions with prior targeted therapies in mRCC patients in the current era. Methods: Inclusion criteria require patients to receive at least one dose of HD IL-2. Patients who received HD IL-2 and had already undergone a post-treatment scan were not eligible. Survival analysis was performed by the method of Kaplan and Meier using datasets as of July 27, 2015. Results: The overall response rate (ORR) and median overall survival (mOS) are described in Table 1. The mOS was not reached (NR) for 364 patients. The 1, 2 and 3 year survival rates were 79%, 63%, and 51%, respectively. For patients with stable disease (SD), the mOS was not reached and the 1, 2 and 3 year survival rates were 96%, 80%, and 60% respectively. There was a significant difference in mOS between SD and progressive disease (PD) patients, NR vs 15.5 months, P<.0001. The mOS was not reached for patients regardless of whether or not they received targeted therapy (TT) prior to HD IL-2. There were 4 reported treatment-related deaths in 364 patients (1.1%), none of these patients had prior TT. Conclusions: PROCLAIM data demonstrate that SD, previously grouped with the non-responders, is associated with extended survival rates. HD IL-2 is an active 2ndline treatment option for patients who have failed TT. These data support that HD IL-2 has a favorable safety profile and remains an effective therapy for eligible patients with mRCC. Clinical trial information: NCT01415167. [Table: see text]